By Tiernan Ray

Shares of Twitter (TWTR) are down $5.55, or almost 8%, at $67.76, reversing weeks of one-day jumps, after Macquarie Equities Research’s Ben Schachter today cut his rating to Underperform from Neutral, and reiterating a $46 price target, in what he says must be “the shortest downgrade note you’ve ever read” because he has not that much to say other than that the stock’s amazing climb is not supported by any change in fundamentals.

“We continue to believe that Twitter as a company has a bright future and many opportunities ahead,” writes Schachter.

“However, as a stock, we believe nothing has changed over the last 15 days to justify the rise in valuation.”

In fact, Schachter has more specific points to make. For one, Twitter had a small syndicate of banks at IPO, and estimates by the vast majority of sell-side analysts covering remain are well above the underwriters’ own estimates for this year despite the non-syndicate banks “receiving no guidance or speaking in any real detail with management.” Estimates are 30% lower among the syndicate than what the Street is currently projecting for 2014’s numbers.

Twitter also will have to staff up to take advantage of the many opportunities in front of it, with only 5% of Google’s (GOOG) headcount, and half the personnel Facebook (FB) has.

“Finally, we note that because of TWTR’s run and rules around price targets, we expect many other analysts will quickly have to either justify raising targets (based on little new information) or downgrade.”

For those of you playing at home, here’s Schachter’s portrait of the disparity in revenue estimates between the Street and the syndicate:

About Tech Trader Daily

Tech Trader Daily is a blog on technology investing written by Barron’s veteran Tiernan Ray. The blog provides news, analysis and original reporting on events important to investors in software, hardware, the Internet, telecommunications and related fields. Comments and tips can be sent to: techtraderdaily@barrons.com.